In vitro macrophage and lymphocyte functions in toxoplasmosis, presumed ocular histoplasmosis, pars planitis, Behcet's Disease, ocular sarcoid, and Wegener's granulomatosis are being studied. The studies are carried out in a simple masked method. Correlations between test results and the clinical condition are being sought and possibly utilized as a guide for specific immunologic therapy. In addition, the test results could shed light on the basic mechanisms of the ocular inflammatory response.